Article spacing system for conveyors



5 Sheets-Sheet 2 BELT ac COMMON cna-2 mm D. W. BEECHER V60 F 7' i Ae-RM//v PER MW J Dec. Z1, 1965 Filed June 19 1963 Ac 6x4-pc) mm a L 0 L CDec. 21, 1965 D. W. BEECHER ARTICLE SPACING SYSTEM FOR CONVEYORS FiledJune 19, 1963 Ac (H5-r) MEMORY o/v 5 Sheets-Sheet I5 Ml? 5' Til/RU Dec.21, 1965 D. W. BEECHER ARTICLE SPACING SYSTEM FOR CONVEYORS Filed June19, 1963 KR 9/ X19/0 P RA-Z R @o ,wu /fc Page? @pa cR z EE/ l 5Sheets-Sheet 4 Dec. 2l, 1965 Filed June 19, 1963 arc-9. 4-6

D. W. BEECHER ARTICLE SPACING SYSTEM FOR CONVEYORS 5 Sheets-Sheet 5 LFRASE #sans PE C OR/NG- HEADS E1 3 jl] HEADS El MG/VE T/C' TPE BAND3,224,557 Patented Dec. 2l, ig

3,224,557 ARTICLE SPACING SYSTEM FR CONVEYRS David W. Beecher,Rockville, Md., assigner to Aerojet- General Corporation, El Monte,Calif. Filed .lune 19, 1963, Ser. No. 289,465 1l Claims. (Cl. 198-34)This invention relates to belts placed upstream of conveyor belts forthe purpose of providing predetermined spacing to packages or articlesto be carried on such conveyor belts. The invention is intended to beused in conjunction with a sorting conveyor system disclosed in acopending application, S.N. 288,928, entitled Improvements in SortingConveyors, Especially for Postal Systems, led contemporaneouslyherewith, lune 19, 1963, and assigned to the same assignee, theinventors therein being: Theodore B. Atanasoff, Stanley W. Kerkering,and Gordon L. Morgret. Reference is made to the copending applicationfor a complete understanding of the present case.

The invention in the aforementioned application relates to sortingconveyors of the type whereon bulk mail postal sacks, or parcel postpackages, parcels, etc., are placed and discharged along the length ofthe conveyor in accordance with particular destinations; for example,states, cities, etc., to which such items are to be forwarded. Thedischarge at various stations along the length of the conveyor is undercontrol of a programming system wherein one or more operators press thekeys of respective keyboards in accordance with a certain destinationcode for each of the items thus placed on the conveyor. The conveyor mayconsist of a continuously moving belt or other type of conveyance, andthe instrumentalities for removing items at predetermined points alongthe length of such belt have heretofore consisted of swinging paddles orother mechanisms which became operative at respective stations,depending on whether or not an item is to be removed, that is, divertedat such stations.

In general, many systems have been devised, particularly for use inlarge post oces, for automatic sorting of bulk mail or parcels in themanner generally described above.

The present invention constitutes an improvement, specifically, in priorart systems which have heretofore been limited to the handling of fairlyregularly shaped objects, and objects of no greater than a particularsize. Further, such prior art systems have, in operation, affordeddamaging shock or impact to packages being diverted and were, therefore,inappropriate for fragile parcels. A further drawback of prior artsystems is the waste in time occasioned by the fact that parcels wereallocated the same amount of linear space on the conveyinginstrumentality, for example a belt, regardless of the actual length ofsuch parcels. Thus, in a system of the conventional prior art, allparcels may be required to be placed on five-foot centers on the belt,even though the parcels be anywhere from six inches to five feet long.Obviously, where packages approached in length the distance betweenplacement centers on the belt, great care was required in centering thepackage lengthwise with respect to the placement point, otherwise, itwould not be properly diverted. In any event, it will be apparent thatthe length of package, that such a system could handle, was limited andthat small packages wasted carrying space and thus, of course, alsowasted running time.

The primary objects of the present invention are to overcome thedrawbacks generally described above and a further object is to provide aconveyor mechanism having simple and rugged parts capable of standing upunder prolonged and heavy wear and wherein worn out parts may be easilyreplaced without the need for complete removal or disassembly of theconveyor. Other 0bjects and features of the invention will be apparentfrom the description to follow.

Briey, the invention comprises a conveyor mechanism in the form of abelt which moves continuously from one or more operator stations to anumber of selective diverting stations in combination with feed belts,which acting prior to the main belt, provide for a certain minimumspacing between parcels thereon. The main belt does not have anydiverting elements, such as paddles, pushers or the like, but of itselfeffects a diverting or article removal function. Thus, the main belt iscomprised of a plurality of tiltable members, such as slats which arepivotally joined by means of link elements in such a manner that anyslat can tilt or rock on an axis which is in the median plane of thebelt and normal thereto. The slats are of such dimension in thedirection of belt movement as to be less than the expected correspondingdimension of articles carried on such belt. For example, a mail sack orpackage may take up the width of several such slats, the width of suchslats being understood as the narrow dimension parallel to the tiltingaxis and in the direction of movement of the belt. The length of theslats is correspondingly understood to be the actual transverse width ofthe belt. Each of the slats carries an element which rides in a trackcentrally disposed with respect to the slat and in the median planethereof and such track is provided with mechanically operable switches,actuated by solenoids, whereby any element or series of elementsconnected to respective slats can be rocked by switching such elementsfrom a track in the median plane to either of the two tracks parallel tothe median track, but displaced transversely and at a higher level.Accordingly, as each such actuating element is switched in eitherdirection to an off-center track, it causes tilting or slanting of therespective slat and a series of such slats arriving at an actuatedswitch would each in turn be individually and gradually tilted from itsinitial horizontal position to a position of some 30 degrees of slant,or suicient to cause transverse sliding of a carried package. Thus,assuming a package rests on four slats, to be discharged onto asecondary chute or conveyor, a solenoid actuated track switch would bedisposed with reference to such secondary conveyor as to etfect tiltingof each Slat individually, beginning at the time that the rst slat onwhich the package rested arrived at the upstream side of such secondaryconveyor, which latter conveyor will be understood to be gene-rallytransversely disposed of the main conveyor. By the time such rst slathad reached approximately half way of the width of such secondaryconveyor, it would be fully tilted to the extent provided by theolf-center tracks and the slats trailing such slat would be experiencinggradual tilt up to the point of full tilt, precisely as was experiencedby the first Slat. Accordingly, the package supported on the four slatswould experience a gradual increasing gravitation force thereonbeginning at its front or downstream end and commences to slide onto thesecondary conveyor. As the fourth slat reaches its full tilt in passingthe secondary conveyor station, the package becomes fully dischargedonto the secondary conveyor. By eecting such a gradual application ofgravitational force, the package is very gently handled in being thusdiverted. Note that no thrust or push member has been applied to thepackage whatsoever and its length is theoretically unlimited, since itmay rest on any number of slate along the length of the main conveyor.It is, of course, understood that package length is limited bytransverse width of secondary conveyors where secondary conveyors areused. However, such limitation is eliminated where packages are allowedto merely slide from the slats onto a large platform. It should furtherbe noted that the track switch remains in slat tilting condition so thatall slats which follow the package carrying slats are likewise tilted;however, the control system enables the track switch to resume centralposition so that slats following any particular package supporting slatswill remain horizontal where they in turn support a package to bediverted at some other point downstream of the diverting stationdescribed above.

From the above description, it will be apparent that the conveyor of theinvention can handle packages and parcels of irregular size, of extremelength, and in a reasonably gentle manner, and that packages may beloaded onto the belt one after the other, there being as a practicalmatter one slat left between each group of package supporting slats soas to avoid any possible interference between packages. Assurance ofsuch single slat spacing between packages is brought about by a seriesof spacing belts or conveyors on which .the parcels are initially loadedand which are provided with progressively varying speeds -underautomatic control to ensure a spacing between the rear of one packageand the front of another, of at least the width of one slat.

The control system is relatively simple in nature considering theversatility of the apparatus. Thus, programming may be eifected byoperators standing at conventional and commercially obtainable keyboardsand there is no problem of package placement at spaced distances, norany need to record package length. By the arrangement wherein all slatsfollowing the initial load bearing slat are tilted provided they carryno load, the need for recording package length, predetermining thenumber of slats that will tilt, is eliminated.

The belt, las `mentioned `above, is ful-ly articulated by means of linkelements pivoted to each other and each such link element carries apivotally mounted slat, such pivotal mounting being effected by a pinpassing through the Slat support element which is normally maintained inthe vertical plane, except when tilting the slat to one side or theother. The entire belt is carried between a pair of sprockets, one ofwhich is powered to effect drive and the other being an idler, suchsprockets being at the belt ends. The individual links are provided withrollers supported in tracks or channels carried on the frame of theconveyor, which may be comprised of angle iron. Thus, a conveyorcomprised of a very large number of slats may be constructed in arelatively simple and economic manner.

A detailed description of the invention now follows, in conjunction withthe appended drawing, in which:

FIG. 1 is a perspective showing a fragment of a slat conveyor belt forpurposes of illustrating the tilting of the slats in conjunction with adiverting station;

FIG. 2 is a fragmentary plan layout showing the arrangement of spacerbelts in tandem with the sorting conveyor belt;

FIG. 3 is an electrical schematic diagram for control of the spacerbelts;

FIG. 4-1 through 4-6 are electrical schematic diagrams for control ofthe slats of the conveyor, in order to effect diverting of packages atva-rious stations, in accordance with a program on magnetic tape;

FIG. 5 is a diagram plan layout showing the relationship between themagnetic tape on which diverting signals are impressed, in conjunctionwith the sorting conveyor and diverter stations.

Referring now to FIG. l, a fragmentary section of a slat conveyor of thetype hereinbefore described is disclosed as a series of slats which willbe understood to form a continuous belt (see FIGS. 2 and 3) and whichare moving in the direction of the arrow. Such slats are all identical,and are identified with the general reference numeral 10. An operatorstands at an operator station at one side of the conveyor and it will beunderstood that he programs packages in accordance with destination witha keyboard 17. More specifically, the control system merely eectsmovement of a solenoid operated mechanical track switch (to bedescribed) at each diverter station, such as diverter station 20 asindicated by the roller type secondary conveyor shown thereat.Accordingly, all slats passing such conveyor will commence to tilt uponreaching the secondary conveyor, and each slat in turn will tileprogressively until it reaches full tilt position. Considering the slatsdesignated as 10a-10e, it will be noted that the slat 10e is beginningto tilt and that the slats downstream thereof are in conditions ofprogressively greater tilt. Thus, it will be appreciated that initially16a experienced the slight degree of tilt shown by the slat 10e when itwas in the position shown for 10e and then experienced gradually greatertilt up to the maximum slant depicted.

The side extension 23 of the secondary conveyor provides a safeguard forexceedingly long packages. Accordingly, any package placed on the groupof slats 10a-10e will thus be gradually slid olf onto the secondaryconveyor. Such package may experience a certain amount of rotation dueto the warping action of the progressively tilting slats, but this is ofno consequence. Downstream of the slat group 10a-10e will be noted ahorizontal group of four slats 10] 101' and this illustrates that suchslats have not been tilted, either because they bore no parcel or theyare bearing a parcel (not shown) to be diverted further on along thelength of the belt. On the other hand, downstream of the horizontalgroup of four slats, 10f-10i, is another group of four slats, 10j-10m,and it will be noted that these are all fully tilted slats. This meansthat they must have borne a parcel which was either diverted at thestation 20, or upstream of the station 20. Accordingly, the slats10j-10i must be carrying a parcel or else they, too, would be in thefully tilted position of the slats 10j-10m since, as noted above, onceany slat starts to tilt, all succeeding slats likewise tilt until a slatis reached which is the rst slat of a parcel carrying group, regardlessof how far down the belt, that is, upstream, such parcel may be.

Control of the conveyor is effected by a memory or programming system toenable an operator or operators to divert parcels selectively at thestations.

The electrical circuitry of the control system is eiective to preventtilting of any slats carrying a parcel where such parcel is intended tobe diverted downstream of a station at which the track switch isactuated. This is brought about by de-energizaion of the latter switchsolenoid responsive to sensing of entry of that parcel on the conveyor,a photoelectric cell being used as a sensing means. Full circuitexplanation will hereinafter be given.

It will, of course, be appreciated that the slats could be spaced apartseveral inches and need not be closely adjacent each other. This would,of course, depend on the nature and size of articles to be handled. Ifnecessary, a flexible rubber or plastic belt may be disposedencompassing all the slats so as to provide support intermediate theslats for articles placed on the conveyor. Of course, such a belt wouldhave to be of sucient llexibility so as to readily yield as the slatstilt. Further, as an economy measure in construction, it would bepossible to have alternate slats merely carried between adjacent slatsas by tension springs or chains, or by any other medium which willeffect proper support and allow relative llexure.

With such an arrangement the supporting posts for alternate slatstogether with the roller carriages therefor could be eliminated. Thus,the roller carriages would be spaced by suitable links suflcient toprovide flexibility of the articulated carriages in going around thesprocket wheels.

Various other modifications of the mechanical arrangement could be made,as will be evident to persons skilled' in the art and the abovediscussion is merely to point out the breadth of the invention.

The spacer system In order to eiect proper operation of the slat beltsorter hereinabove described, it is essential that all slats under aparticular parcel eifect tilt at a designated diverting station. Toachieve this, proper spacing of parcels in the direction of ow isnecessary. The system hereinbelow described, prevents two parcels fromresting on the same slat and in fact ensures a separation betweentrailing and leading ends of consecutive parcels so as to maintain aspacing of more than one slat width in the ow direction between suchparcels.

Thus, in actual practice with an operating machine, a minimum spacing ofl2 is desired, whereas the slat width is approximately 8 with one inchspace between slats.

The spacing system for assuring proper separation between parcels, isshown in conjunction with FIGS. 2 and 3 wherein FIG. 2 shows the tandemdisposition of the conveyor belt and a series of spacer conveyor beltsdesignated as Belt 1, Belt 2 and Belt 3.

Packages are initially loaded on Belt 1. Assuming that the desired speedof conveyor 10 is 180 feet per minute, an appropriate speed for Belt 1could -be 135 feet per minute, and this belt could be kept continuouslyrunning under usual loading conditions. The normal speed of Belt 2 wouldthen be 155 feet per minute and that of Belt 3 would be 180 feet perminute, and these latter belts are driven by a common motor M through apulley system as shown. The motor is of a type which can start and stopvery rapidly, being equipped with suitable automatic braking for quickstop. The motor may be operated from a three-phase line through thesolenoid operated motor starter, MS, having contacts in four lines L1,L2, `L3 as shown.

At the downstream end of Belt 3, there is arranged a light which sends abeam across the belt to a photo-cell PC and it will be understood thatany package crossing between the light and the cell, will interrupt thebeam.

Assuming that packages 3 feet long are placed on Belt 1, end to end,that is on 3 feet centers, their center to center spacing would be 180 3ft. X 135 or 4 feet, in going from Belt 1 to the conveying belt.Accordingly, the space between consecutive packages would be one foot.

It can be assumed that parcels are frictionally gripped at their centersof gravity in moving to a successive belt and that such centers ofgravity are at parcel centers. This would not usually be the case, butthe system is operative as described regardless of random center ofgravity spacing.

`Where the end to end spacing is one foot there would be no need forBelts 2 and 3. However, assuming that packages are only 11/2 feet long,their center to center spacing, when placed on Belt 1, would then beonly 11/2 feet and at the time of arrival at the sorting conveyor belt,such spacing would only be 2 feet. The spacing between packages wouldthen be only 6" and additional spacing is required to ensure accuracy indiverting. By means of the Belts 2 and 3 which stop and start responsiveto conditions of spacing, parcels are spaced further apart when sensedat less than one foot spacing.

A general description and operating of the spacing control system is asfollows: Condenser C (FIG. 3) has a time rate of discharge via variableresistance R3 that corresponds to the desired spacing as a matter oftravel time of articles on Belt 3. Thus, R3 is variable to predeterminesuch spacing, and condenser C discharges through R3 as long as thephotocell is illuminated. On the other hand, C is charged while anarticle is passing the photo-cell, charging being accomplished quicklythrough resistance R2, which resistance is for preventing 6 excesscurrent rather than limiting the rate of charge, since it is desired tocharge C as rapidly as possible but to discharge it through the timeconstant circuit which comprises R3-C while the cell is illuminated.

The extent of discharge of C (FIG. 3) determines whether or not Belts 2and 3 are operative. If the parcels are too close, insucient dischargeoccurs due to the cell being darkened too soon by the upstream parcel.The motor stops substantially as soon as the beam is blocked by theupstream parcel and it remains stopped long enough for the downstreamparcel to be carried off on conveyor 10 so as to effect a one footspacing before the upstream parcel is again moved.

A pair of transistors (PNP type) are provided, one of which, TR1, isresponsive to the article sensing means, i.e., the photocell PC tocondition certain relays for control of charge and discharge of C, and atransistor TR2 which controls the actual starting and stopping of motorM via relay means responsive to charged or discharged condition of C.

Accordingly, whether or not the motor starts or stops is a matter of thetime occurring between illumination and darkening of PC which depends onthe spacing between the trailing edge of a parcel and the leading edgeof a successive parcel, as compared with the time constant of R3-C,which is designed so that C will discharge if the spacing is a foot ormore.

The detailed description and operation of the motor control circuit ofFIG. 3 now follows.

Assume no articles on the Belts 1 and 2, and the motor M is running,energized from the A.C. lines, current passing through MS via relaycontacts of circuitry to be hereinafter described. The photocell PC isilluminated, the transistor TR1 being biased thereby to conduct.Photocell PC is a photo resistive type and is in series with a resistorR1 having a value about midway between the light and dark resistance ofthe cell. Thus, conducting bias for TR1 (base negative and emitterpositive) is effected by the D.C. common line to the emitter and throughphotocell PC from the -24 v. line V1 to the base, wherein the commonline has a potential midway between -24 v. and |24 v., the total voltageIbeing 48 v. between negative and positive lines V1 and V2,respectively. Condenser C, which was charged from the line V2 (positive)via R2 when the system was turned on has discharged via R3-C to line V1(negative) for the reason that current through TR1 has activated a relayCRA in the collector circuit to line V1. Thus, contact CRA-1 activates arelay CRB to close contact CRB-3 in series with condenser C effecting adischarge path to line V1. As long as the photocell remains illuminated,the condenser C remains discharged, assuming no parcel blocks the beam,and current for MS thus passes through contact CRA-2, and also through acontact CRC-2 of a relay CRC, responsive to a conducting condition oftransistor TR2, but no MS current passes through NC contact CRB-4 whichis open at this time (CRB energized).

Transistor TR2 is connected across the D.C. lines V1 and V2 with therelay CRC in series with the transistor output. [When TR2 conducts,relay CRC is energized and contact CRC-2 maintains energization of themotor starter solenoid MS to keep the motor running, even should relayCRA become deenergized whence CRA-2 would be opened.

As long as no article interrupts the beam, the above condition obtains,i.e., relays CRA, CRB, CRC are activated, transistors TR1, TR2,continuously conduct, no

charging current from line V2 line goes to the condenser C and thelcondenser is discharged.

Transistor TR2 remains conducting (base negative and emitter positive)due to the state of discharge of condenser C; the NC contact CRB-2 inseries with R2 being open, no charge can go to condenser C from line V2,and SRE-2 being closed current from line V1 can pass to the I ase.

However, 'TR-2 becomes biased to cut ott (base becomes positive) shouldcondenser C become charged positively from line V2 and this chargeoccurs very rapidly should the cell be darkened by parcel interruptionof the light beam. Such interruption also causes transistor TR1 to bebiased to cut-01T due to the large voltage drop across the photocellwhen it is darkened which removes negative bias from the base and leavesa positive bias via R1.

Thus, assume the leading edge of a package cuts off light to thephotocell PC. The collector current for TR1 is cut off, deactivatingrelay CRA to open contact CRA-1 which de-energizes relay CRB. Since CRBis still energized, current is broken through contact CRB-1 which wouldotherwise serve as a sealing-in contact for relay CRB if NC contactCRC-1 were closed. However, the motor starter MS is still activated viacontact CRC-2, although CRA-2 is now open. Further, contact CRB-3 openswhile contact CRB-2 and CRB-4 close at this time. This elects chargingof the condenser to 24 v., thereby biasing transistor TR2 to cut off,which then deactivates relay CRC. This, of course, occurs very rapidly,as explained above, the resistance R2 being merely to prevent excesscurrent ow to the condenser, which might be harmful, and does notconstitute any part of a time constant circuit except to the extent ofprotecting the condenser. Since contacts CRC-2 and CRA-2 are now bothopen, maintenance of activation of the motor starter MS is effected onlyby Way of NC contact CRB-4, closed due to present deactivation of relayCRB. Accordingly, at this time the motor starter MS remains activatedand the Belts 2 and 3` continue to run as long as the parcel or articleis passing the photocell.

The above sequence of events conditions the system to effect stopping ofthe motor should the leading edge of the next successive article be lessthan a foot upstream of the preceding article, while at the same timemaintaining the system in condition to permit continued motor operationshould the next successive article be a foot or more upstream.

This conditioning of the system permits control by the setting of thevariable resistor R3 such that the discharge time of the condenser C tothe point where transistor TR2 becomes conducting again, responsive toillumnation of the photocell after the package passes, is set tocorrespond to one foot of movement of the parcels on Belt 3.

Thus, assuming the leading edge of a second package is spaced a foot ormore from the trailing edge of the downstream package. When the rstpackage passes completely, the photocell is illuminated, CRA isenergized via TR1 as once more conducts. CRB is energized; contact CRB-2opens, charging current is cut 0E, while CRB-3 closes to permit thecondenser discharge. The condenser C has time to discharge through R3 inthe time that the photocell is illuminated, the light beam passing, ofcourse, through the foot or more spacing between the two packages.

Forward bias is thus restored to transistor TR2, effecting energizationof relay CRC via collector current, and all previous conditions are thusrestored wherein CRA-2 and CRC-2 are closed, while CRB-4 is open. Themotor starter remains energized via CRA-2 and CRC-2.

Assume, however, that the spacing between two successive packages isless than one foot in passing the beam. Beam cut off by the leading edgeof the second package renders transistor TR1 non-conductive prior to thetime condenser C can discharge to the point where TR2 becornesconducting. Accordingly, relay CRC remains deenergized and relay CRA nowbecomes de-energized. However, relay CRB remains energized since CRB-1seals it in in series with the normally closed contact CRC-1. Thus,contact CRB-4 is open. Since CRA-2 was opened due to cut ot oftransistor TR1 and CRC-2 is open due to continued cut olf of transistorTR2, the opening of all 8 such contacts cuts out the motor starter tostop the motor.

Thus, the Belts 2 and 3 cease motion and the package on Belt 3 blocksthe beam at the downstream end of the belt, remaining there untilcondenser C fully discharges to the point where TR2 becomes againconductive. By this time the proceding package has been carried oil bythe conveyor 10, and thus there is at least one foot of space providedbetween the stationary package and the preceding package. Upon TRZbecoming once more conductive after condenser discharge, relay CRC isagain activated, CRC-2 closes and the motor starter is again activatedwhence the belts renew their motion. At this time CRC-1 opens todeactivate CRB and thus closes the normally closed contact CRB-4.Likewise CRB-3 opens and CRB-2 closes to again charge the condenser tobias the transistor TR2 to cut off, whence relay CRC is againdeactivated, conditioning the system for the next package interruptionof the light beam.

In substance, therefore, the contact CRC-2 maintains the belts runningas long as transistor TR2 is conductive, the Contact CRA-2 maintains thebelts running as long as 4the photocell is illuminated and the contactCRB-4 maintains the belts running so long as there is at least one footspacing between successive packages.

In order to insure proper operation of the system the condenser cancharge through the resistor R2 in approximately 1/100 of the time thatit can discharge through resistor R3. This permits operation of thesystem in response to packages as small as some two inches in length.

The memory system Reference is made to FIGS. 4-1 through 4-6 showing thecircuitry for programming the conveyor to divert parcels olf the belt atselected designations, and to FIG. 5 showing the diagrammaticrelationship between a magnetic tape record and the slat conveyor 10.

Referring particularly to FIG. 5, it will be noted that the magnetictape and the slat conveyor have a common drive such as any suitablemotor-driven means G, e.g., gearing or the like, powered by a motor (notshown).

The magnetic tape has extending transversely thereacross a series oferase heads upstream of respective recording heads. It will beunderstood that there are twelve heads of each set disposed over twelverespective recording channels on the tape and that there are twelverespective readout heads, e.g., 9; 10'; downstream to correspond inlongitudinal position to the locations of the various track switchesalong the conveyor.

The recording heads are disposed one slat width downstream of thephotocell PE which senses parcels as they enter the conveyor upstream ofthe diverting stations. The track switches are generally indicated asSwitch 1, Switch 2, Switch 3, Switch 4 Switch 9, Switch 10, Switch 11,Switch 12, corresponding to Channel 1, etc., on the tape, as will beclearly understood from the drawing. Thus, readout head 9 over Channel 9controls track Switch 9, and is spaced from readout head 10 whichcontrols track Switch 10 in the same ratio as the spacing between trackSwitches 9 and 10.

Accordingly, as the tape and the conveyor move, the erase heads firstclear the tape of previous signals whence the recording heads can recordsignals in their respective channels for each track switch to beoperated. Thus, a signal, e.g., in Channel 10 will be picked up byreadout 10 at a time that a parcel is approaching track Switch 10 andthe switch will be operated by its solenoid to commence tilting theslats on which the parcel rests in a manner heretofore described.

The programming of the tape is illustrated in the present instance in asimplified system -utilizing a single operator rather than severaloperators, but it will be understood that a multi-operator system couldbe used, it then being necessary, of course, to provide suitablecircuitry ot the kind to be described for each operator withinterlinking circuitry to ensure proper sequence for programming. Forexample, if two or more operators wish to divert respective parcels atSwitch 9, it is, of course, necessary to have delay circuit for holdingthe separate signals for sequential recording. Referring to FIGS. l, 2,4 1, 4 2, an operator would be positioned at a loading point forconveyor 10 and he has a series of push buttons PB-l through 13B-12,only the first lfour `being illustrated in FIGS. 4 1, 4 2, since allothers are a duplication of the system arrangement. Thus, as a parcel isloaded, say on Belt 1 of the scraper system (FIG. 2), the operator notesthe designation insofar as it pertains to a diverter station on conveyor10 and presses the corresponding push button to record a signal on themagnetic tape which signal at the time of readout has moved under areadout head corresponding to the selected diverter station, effectingtilting of the slats at that station, this being the time of arrival ofthe parcel of that station.

Referring now to FIGS. 4-1 and 4 2, each of the push buttons connects toa corresponding so called MR relay which is a signal storing relay, suchas MR1, MR2 MR12, etc., activated at the time the respective button ispushed. Such activation effects storage of the signal until subsequentlyacting signal recording control KR relays, or coding relays, such asKR1, KRZ KR12, etc., corresponding to respective relays MRI, MR2, etc.,have been reset to remove any previous activation which they may havehad. The MR relays then transfer the respective stored signals to thecorresponding KR relays, causing respective activation thereof to applya 1000 c.p.s. signal to a respective tape channel. Such signal is placedon the tape so that it will reach the appropriate readout head justbefore the slat under the leading edge of the programmed parcel reachesthe appropriate track switch controlled by that readout head. The KRrelays are sealed in energized condition until the next parcel has beenloaded on Belt 1 and is programmed. However, if no further parcel isthus programmed the track switch at that station will remain in actuatedcondition and, thus, tilts all slats passing the station, indefinitely.If another parcel `is programmed, the KR relays are reset, such tiltingeffect ceasing.

The above describes the general operation of t-he memory system, adetailed description of which will now follow.

A light L and photocell PE (FIG. 5) are arranged adjacent the upstreamend of conveyor and it will be understood that the coding push `buttonsPE1, etc. (FIGS. 4 1, 4 2) are pressed before a parcel interrupts thebeam from the light to the cell. Actuation of a push button activatesthe corresponding MR relay which seals in through a normally openContact, for example MRI-1, MR2-1, etc. to store the signal. Theenergizing current is from the A.C. lines l and 2 shown, the common pushbutton line 3 being shown connected to line 1 in FIG. 4 2. Activation ofany such MR relay in the manner described closes a second contact suchas MR-I-Z (FIG. 4 2) which energizes relay CRG to open its normallyclosed contact CRG-l extinguishing a Selection lamp which indicates thata code signal has been entered in the system. At the same time normallyclosed contact CRG-Z (FIG. 4 2) is opened which disconnects the pushbutton common line 3 from A.C. line 1 so that all push 'buttons thenbecome momentarily inoperative against entry of a subsequent signal.

Any MR relay thus activated remains activated until the parcel for whichit has been coded breaks the photocell beam. At this time the photocellceases to conduct.

The photocell is of a photoresistive type having relatively highconduction when illuminated. It is in series with the resistor R4 acrosspositive and negative D.C. lines as shown (FIG. 4 3). Resistor R4 isabout half the dark resistance of the cell and D.C. current is affordedthereto by the full wave rectifier R0 powered by the transformer'transistor again becomes non-conductive.

T connected to the A.C. lines 1 and 2. The photocell controls operationof a transistor TR1 which is nonconductive when the cell is illuminated,due to lack of emitter current since the emitter and `base aresubstantially at the same potential 'by virtue of the high conductivityof the illuminated photocell, as will be understood from FIG. 4 3,wherein the diode D has no effect on bias current for the transistor,but permits discharge of a condenser C2.

Thus, when current ceases to flow through the photocell, as when aparcel is passing it, the dark resistance is high and the base of TR1 isrendered negative via resistor R4 and condenser C2 and the transistorthen passes current to relay EE to energize that relay. Suchenergization is momentary and lasts only until the capacitor C2 issufficiently charged so than base current ceases and the The value of C2is such that relay EE is energized for some 30 to 50 milliseconds. Uponrestoration of the light beam, the package completely passing it, thecapacitor rapidly discharges through the photocell and also through adiode D so that the circuit is prepared to repeat the momentaryenergization of relay EE for the next package.

When EE. is energized the closure of contact EEl energizes a relay CRIwhich in turn ener-gizes a relay DRA (FIG. 4 4) through contact CRI-1.Relay DRA seals in through its contact DRA-1 and also through normallyclosed contact CRS-1 of a relay CRS.

The energization of relay DRA conditions the circuit for the nextclosure of a cam-operated contact P which sets -up a train of eventsthat de-energizes all KR relays as explained below. Contact P closesmomentarily each time the leading edge of a slat aligns transverselywith the photocell and it will be understood that a suitablesynchronizing drive (not shown) is present to rotate the cam PC in orderto achieve the desired function.

Since DRA is energized, closure of contact P energizes relay CRZ viacontact DRA-2 (FIG. 4 3) by virtue of the series connection across theD.C. lines.

Energization of relay CRZ opens thenormally closed contact CRZ-1 (FIG. 43) and thus deenergizes all KR relays by disconnection from A.C. line 1.At the same time, contact lCRZ-2 closes the CRZ-3 opens which chargesthe capacitor C3 '(FIG. 4-4). All this occurs as switch P closes;however, as soon as P opens in the course of rotation of cam PC, CRZ isdeenergized so that CRZ-2 opens and CRZ-3 closes, to permit C3 (FIG. 44) to discharge through the relay CRZ whence energization of that relayoccurs for a short duration, 30 to S0 milliseconds as determined by theval-ue of C3, and results in the application of power to the contactsMRI-3 through MRlZ-S of the MR relays via contact CRZ-1 (FIG. 4 2) fromA.C. line l. These MR contacts are connected to respective KR relays,whereby any KR relay corresponding to an MR relay energized by aselected push button, is energized.

Accordingly, the respective KR contact (FIG. 4 4) such as KR1-2, KR2-2,etc., is closed to send a 1000 c.p.s. from a conventional oscillator(FIG. 4 4) as a continuous signal to the respective tape channelrecording head whence the signal is recorded in a respective channel.The length of the signal is determined by the length of time theparticular KR relay is energized which in `turn depends on light beaminterruption by the next package.

As the tape moves, the signals are picked up by the respective readoutheads (FIG. 4 5) e.g., readout heads 9 and 10', which acting throughrespective amplifying transistors, such as TR9, TRI, etc., energizesrespective relays, RRQ, RRlt), etc., to close respective contacts RRQ-1,RRl-l, etc., thus energizing the solenoids SR9, 8R10,y etc., havingrespective contacts S'R9 1, SR'10-1, etc., which cause actuation ofrespective track switch solenoids at the diverting stations to operaterespective track switches.

Further, momentary energization of relay CRZ as described above alsocloses contact CRZ-Z (FIG. 4-4) which permits charge of capacitor C4from the D.C. lines; as soon as CRZ is de-energized upon completion ofdischarge of C3 therethrough, normally closed contact GRZ-3 closes tomomentarily actuate relay CR3 by discharge of C4 therethrough. Thus,normally closed contact CRS-1 is opened y(FIG. 4-4) as well as normallyclosed contact CR3-2 (FIG. 4-2). This deenergizes relay DRA (relay CRIde-energized to open CRI-1 when EE is deenergized) and all MR relays,the sealing current being broken for these relays. Deenergization of theMR relays effects deenergization of relay CRG (FIG. 4-2) due to openingof contacts MRI-2 through MR1-12. Accordingly, the NC contact CRG-1 isclosed to light the Selection light, indicating the system may be codedfor the next parcel, since all push buttons are now again live due toclosing of NC contact CRG-2 (FIG. 4-2) when CRG was lde-energized.

All KR relays remain actuated due to sealing in at NC contact CRZ-l(FIG. 443) and remain actuated until the entire sequence is repeated byanother parcel interrupting the light beam to cut off cell PE, thusenergizing CRZ to open CRZ-l.

As shown in FIG. 4-2, a cancel switch is provided in series with lines 1and 4. In the event the operator miscodes a parcel, pressing of thisbutton switch cuts the current to all MR relays via their sealingcontacts thus neutralizing the previously stored signal.

Due to the continued activation of any coded KR relay until a succeedingparcel interrupts the light beam, all slats reaching the respectivetrack switch will be tilted and remain tilted until they arrive at thedrive sprocket wheel at the end of the conveyor, as explained in theco-pending application.

All recordings are erased as the tape passes under the erase heads andthe tape channels are then ready for fresh programming.

In summation of the above discussion:

A parcel is programmed by an operator pressing a push button at the timethe parcel is loaded onto the conveyor or onto any entrance belt, butupstream of the photocell. The photocell controls all functioning of thecircuity described. Pressing of a selected button effects signal or codestorage in a storage (MR) relay. At this point, the selection has beenmade and the selection lamp shown in FIG. 4-2 is extinguished so that nofurther selection will be made by the operator until that light is oncemore lit.

The system is thus conditioned for recording the signal on the tape bandand this occurs when the parcel programmed interrupts the light beam.

At that time a connection is completed to cam switch P which switch iscontinuously closing and opening with each slat passing the beam, sothat on the next closure of cam switch P after the beam is interruptedby a parcel all previously energized code relays, that is KR relays, aredeenergized. Subsequently, switch P opens and the code relay for whichthe respective storage relay has been energized is then likewiseenergized. Following a short delay, due to the effect of condenser C4,such storage relay is then deenergized and the selection light is litonce more, apprising the operator that the neXt parcel may be coded.

Accordingly, the automatic deenergization of the coding relays dependsupon the occurrence of three sequential conditions:

(l) Operator makes a station selection by pressing a coding push button(2) The beam is interrupted when the programmed parcel passes thesensing means, i.e., the photocell (3) Switch P closes.

opening of the switch P.

Any coding relay thus energized effects actuation of a respectivesolenoid track switch-via the recording tape and readout system, andsuch track switch remains actuated to continually tilt all slats:arriving that station. This condition remains until the respective coderelay is deenergized which can occur only by the sequence enumeratedabove, namely, the programming of another parcel. Thus, if no subsequentparcel is put on the conveyor, the slats will continually be tilted atan actuated track switch for as long as the conveyor runs. It willreadily be seen that the length of signal on the tape band is then onlya function of the spacing between successive parcels and is in no sensea function of the length of any particular parcel.

The same storage relay may be selected twice in a row, if it is desiredto divert successive parcels at the same station. This is made possibleby deenergization of all storage relays each time the switch P opens.Such deenergization occurs with suitable delay (a function of condenserC4) in order to ensure energization and recording functioning 4of thesame lselected coding relay which likewise occurs upon opening of theswitch P and which is to be again selected.

What is claimed is:

l. In a system for effecting a predetermined spacing between articles, apair of tandem belts operating at a predetermined speed ratio andcomprising an entrance belt and a discharge belt wherein said entrancebelt runs at a slower speed than said discharge belt, means foreffecting simultaneous starting and stopping of said belts comprisingarticle sensing means disposed at the discharge end of said dischargebelt, and circuitry means for stopping said belts responsive to spacingbetween articles as sequentially sensed by said sensing means whensuccessive articles are spaced less than a predetermined distance apartwhen the downstream article is leaving the discharge belt, saidcircuitry means being operative to start said belts a predetermined timethereafter.

2. In a system as set forth in claim 1, said circuitry means comprisinga time constant circuit predetermined to discharge in a timecorresponding to a desired spacing between articles.

3. In a system as set forth in claim 2, said time constant circuitcomprising a condenser, means for charging said condenser while anarticle is passing said sensing means, and comprising means foreffecting discharge when said article has passed said sensing means, andfurther comprising motor control means responsive to the charged ordischarged condition of said condenser to respectively stop or startsaid belt.

4. In a system as set forth in claim 3, wherein the rate of charge issubstantially greater than the rate of discharge whereby said condensermay be charged relatively rapidly upon sensing of an article by saidsensing means.

5. In a system as set for-th in claim 3, said sensing means comprising aphoto-resistive photocell, a transistor disposed to be biased to cut offwhen said cell is substantial- `ly non-conducting, relay meansresponsive to transistor cut-off to effect charging of said condenserand responsive to current conduction through said transistor to effectdischarge when said photocell is conducting.

6. In a `system as set forth in claim 3, said circuitry means comprisinga transistor and relay means disposed to condition said motor controlmeans to effect starting of said belts when said transistor isconducting and to effect stopping lof said belts when said transistor isnon-conducting, said condenser being connec-ted to effect bias on saidtransistor -so as to render said transistor conductive when saidcondenser is discharged and non-conductive when sai-d condenser ischarged.

7. In a system as set forth in claim 3, said sensing means comprising laphoto-resistive photocell, -a transistor disposed to be biased to cutoff when said cell is substantially non-conducting, relay meansresponsive to tran-sistor cut-off to effect charging of said condenserand responsive to current conduction through said transistor to effectdieharge when said cell is conducting, said circuitry means -comprisingan `additional transistor and relay means disposed to condition saidmotor control means to effect starting o-f said belts when saidadditional transistor is conducting and to effect stopping of said beltswhen said additional transistor .is non-conducting, said condenser beingconnected to effect bias on said additional transis- `tor' so as torender said transistor conductive when said condenser is discharged andnon-conductive when said condenser is charged.

8. In a vsystem as set forth in claim 1, including a source of D.C.having a negat-ive line, a positive line, and a common line at anintermediate potential, said common line and one of Said -other linesbeing connected to said condenser for charging thereof, said condenserbeing connected thru a resistor to the other of said other lines fordischarge, and said condenser being connected to said additionaltransistor for bias control thereof.

9. In a system for effecting a predetermined spacing between articles, apair of tandem belts operating a-t a determined speed ratio andcomprising an entrance belt and a discharge belt wherein said entrance-belt runs at a slower speed than said discharge belt, vmeans foreffecting simultaneous starting and stopping of said belts comprising anarticle-sensing means disposed at the discharge end of said dischargebelt, .and circuitry means for stopping said belts responsive to spacingbetween articles as sequentially sensed by said sensing means whensuccessive articles are spaced less than a predetermined distance apartwhen the downstream article is leaving the discharge belt, and forstarting said belts a predetermined time thereafter, said circuitrymeans comprising a time constant circuit predetermined to discharge in atime corresponding to a desired spacing between articles, said timeconstant circuit comprising a condenser, means for charging saidcondenser while an article is passing said sensing means, and comprisingmeans for effecting discharge when said article has passed said sensingmeans, and further comprising motor control means responsive to thecharged or discharged condition of said condenser to respectively lst-opor start said belt.

10. In a system for effect-ing a predetermined spacing between articles,a pair of tandem -belts operating at a predetermined speed ratio `andcomprising an entrance -belt and a discharge belt wherein said entrancebelt runs at a slower speed than said discharge belt, means foreffecting simultaneous starting yand stopping of said belts comprisingan article-sensing means disposed at the discharge end of said dischargebelt, and circuitry means for stopping said belts responsive to spacingbetween articles `as Sequentially sensed by said sensing means whensuccessive articles are spaced less than a predetermined distance apartwhen the downstream article is leaving the discharge belt, and forstarting said belts a predetermined time thereafter, said circuitrymeans comprising a time constant circuit predetermined to discharge in atime corresponding to a desired spacing 'between articles, said timeconstant circuit comprising a condenser, means for charging saidcondenser While an article is passing .said sensing means and comprisingmeans for effecting discharge when said art-icle has passed said sensingmeans, `and further comprising motor control means responsive to thecharged or discharged conditions of said condenser to respectively stopor start said bel-t, said motor control means comprising relay means-having a plurality of motor starter control contacts, said relay meansbeing operative to individually open or close respective contactsresponsive to the spacing of an Iarticle leaving said discharge beltrelative lto an article upstream thereof, wherein at least one suchcontact is normally open and is closed responsive to failure of saidcondenser to discharge to `a predetermined extent.

11. In a system for effecting a predetermined spacing between articles,a pair of tandem belts operating at a predetermined speed ratio andcomprising an entrance belt and a discharge lbelt wherein said entrancebelt runs at a slower speed than said discharge belt, means foreffecting simultaneous starting and stopping of said belts comprising anarticle-sensing means disposed at the discharge end of said dischargebelt, and circuitry means for stopping said belts responsive to spacing`between articles as sequentially sensed by said sensing means whensuccessive articles are spaced lless than a predetermined distance apartwhen the downstream article is leaving the discharge belt, and forstarting said belts a predetermined time thereafter, said circuitrymeans comprising a time constant circuit predetermined to discharge in atime corresponding tio a desired spacing between articles, said timeconstant circuit comprising a condenser, means for charging saidcondenser while an article is passing said sensing means, and comprisingmeans for effecting discharge when said article has passed said sensingmeans, `and further comprising motor control means responsive to thecharged or discharged condition of said condenser to respectively stopor start said belt, said motor control means comprising means having aplural-ity of motor control contacts, said rnotor control means beingoperative through said circuitry means to individual-ly open `or closerespective contacts to stop and start said motor responsive to the stateof discharge of said condenser.

References Cited bythe Examiner UNITED STATES PATENTS 2,130,323 9/'1938Lueckel 198-21 2,184,905 12/1939 Brintnall 198-34 2,549,281 4/1951Armstrong 198-34 2,816,647 12/1957 Ruth 198-34 2,984,366 5/11961Grelle-r 214-11 3,024,890 3/1962 Belk 214-34 3,075,630 1/1963 Fisk198-76 3,096,871 7/1963 Anderson 214-11 X GERALD M. FORLENZA, PrimaryExaminer. MORRIS TEMIN, HUGO O. SCHULZ, Examiners.

1. IN A SYSTEM FOR EFFECTING A PREDETERMINED SPACING BETWEEN ARTICLES, APAIR OF TANDEM BELTS OPERATING AT A PREDETERMINED SPEED RATIO ANDCOMPRISING AN ENTRANCE BELT AND A DISCHARGED BELT WHEREIN SAID ENTRANCEBELT RUNS AT A SLOWER SPEED THAN SAID DISCHARGE BELT, MEANS FOREFFECTING SIMULTANEOUS STARTING AND STOPPING OF SAID BELTS COMPRISINGARTICLE SENSING MEANS DISPOSED AT THE DISCHARGE END OF SAID DISCHARGEBELT, AND CICUITRY MEANS FOR STOPPING SAID BELTS RESPONSIVE TO SPACINGBETWEEN ARTICLES AS SEQUENTIALLY SENSED BY SAID SENSING MEANS WHENSUCCESSIVE ARTICLES ARE SPACED LESS THAN A PREDETERMINED DISTANCE APARTWHEN THE DOWNSTREAM ARTICLE IS LEAVING THE DISCHARGE BELT, SAIDCIRCUITRY MEANS BEING OPERATIVE TO START SAID BELTS A PREDETERMINED TIMETHEREAFTER.